Mapping process changes

ABSTRACT

In one implementation, a computer-implemented method includes receiving a request to run a particular process; determining whether the particular process is to be run in isolation on the computer system; selecting a particular permission scheme from among a plurality of permission schemes based, at least in part, on one or more characteristics of the particular process; fetching, according to the particular permission scheme, a copy object that corresponds to an actual object for the particular process, wherein the copy object is instantiated in an isolated environment; running the particular process is isolation on the computer system by executing the copy object in the isolated environment; applying, according to the particular permission scheme, one or more changes to the copy object; and mapping, according to the particular permission scheme, the one or more changes in the copy object to the actual object.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/172,679, filed Jun. 8, 2015, and titled “Mapping Process Changes,”which is incorporated by reference.

TECHNICAL FIELD

This document generally describes technology related to mapping processchanges on computer systems.

BACKGROUND

Computer applications (e.g., web browser applications, browser-basedapplications, thin client applications, standalone applications) thatare run on computing devices (e.g., laptop computers, desktop computers,mobile computing devices, computer systems) by one or more processorscan include any number of computer processes that are executed by theone or more processors to provide the applications. For example, a webbrowser application may include separate processes that are executed andcommunicate with each other to retrieve, render, and output web pages,such as web pages that use one or more browser plugins.

Computer processes that are executed on a computer may pose securityrisks, such as the processes making unwanted changes on the computer(e.g., permission changes, data corruption, network settingsmodifications) and/or unauthorized accessing of sensitive information(e.g., private user information, financial information). A variety ofsecurity mechanisms have been used to minimize the potentially negativeeffects of such computer processes, such as sandboxing processes(running processes in isolated environment), running processes onvirtual machines (emulation of a computing environment), using antivirussoftware, implementing various network firewalls, using encryption forstored information, and using certificates to authenticate permission ofvarious operations.

SUMMARY

This document generally describes applying and/or mapping changes fromprocesses being executed in isolation to the actual underlying processes(and associated data, such as objects for the processes) based on avariety of different permission schemes. Permission schemes can beselected based on one or more attributes associated with processes, suchas characteristics of the processes. For example, a proactive permissionscheme can be used to obtain user permission for changes to be mappedfrom an isolated process back to the actual process in advance of anychanges being received when the copy of the process is running inisolation. In another example, a reactive permission scheme can be usedto obtain user permission for each change as it is to be mapped from anisolated process back to the actual process. In a further example,reactive permission schemes can additionally and/or alternatively group(batch) similar changes (e.g., write( ) command) and apply them togetheronce a single user permission has been received for applying the changesin the group/batch.

In one implementation, a computer-implemented method includes receiving,at a process manager running on a computer system, a request to run aparticular process on the computer system; determining, by the processmanager, whether the particular process is to be run in isolation on thecomputer system; selecting, by the process manager and in response todetermining that the particular process is to be run in isolation, aparticular permission scheme from among a plurality of permissionschemes based, at least in part, on one or more characteristics of theparticular process, wherein each of the plurality of permission schemesdefines a different set of permission requirements for applying changesto a process being run in isolation; fetching, by the process managerand according to the particular permission scheme, a copy object thatcorresponds to an actual object for the particular process, wherein thecopy object is instantiated in an isolated environment on the computersystem; running the particular process is isolation on the computersystem by executing the copy object in the isolated environment;applying, by the process manager and according to the particularpermission scheme, one or more changes to the copy object; and mapping,by the process manager and according to the particular permissionscheme, the one or more changes in the copy object to the actual object.

Such a computer-implemented method can optionally include one or more ofthe following features. The plurality of permission schemes can include,at least, (i) a proactive permission scheme in which user permission isobtained in advance of all changes being received for the copy object,and (ii) a reactive permission scheme in which user permission isobtained in response to each change that is received for the copyobject, and (iii) a reactive batching permission scheme in which userpermission is obtained in response to a batched group of changes thatare received for the copy object. The particular permission scheme caninclude the proactive permission scheme. The computer-implemented methodcan further include outputting, by the computer system and beforefetching the copy object, information to prompt a user to providepermission for changes to the copy object in advance of any changesbeing made; and receiving, at the computer system and before fetchingthe copy object, user input comprising permission for changes to thecopy object. The copy object can be fetched in response to the userinput being received. The particular permission scheme can include thereactive permission scheme. The computer-implemented method can furtherinclude outputting, by the computer system after fetching the copyobject and before applying the one or more changes to the copy object,information to prompt a user to provide permission for each of the oneor more changes to the copy object; and receiving, at the computersystem and before applying the one or more changes to the copy object,user input comprising permission for each of the one or more changes tothe copy object. The one or more changes cam be applied to the copyobject in response to the user input being received. Thecomputer-implemented method can further include outputting, by thecomputer system after applying the one or more changes to the copyobject and before mapping the one or more changes to the actual object,information to prompt a user to provide permission for each of the oneor more changes to the copy object; and receiving, at the computersystem and before mapping the one or more changes to the actual object,user input comprising permission for each of the one or more changes tothe copy object. The one or more changes can be mapped to the copyobject in response to the user input being received.

Such a computer-implemented method can further include obtaining, by theprocess manager, an indication that another version of the actual objectis running as part of another process on the computer system. The one ormore changes to the copy object can be mapped to the actual object inresponse to obtaining the indication. Such a computer-implemented methodcan further include determining a likelihood that the copy object willrequire multiple mappings to the actual object within a threshold periodof time; selecting a particular isolated storage scheme from among aplurality of isolated storage schemes based, at least in part, on thelikelihood that the copy object will required multiple mappings withinthe threshold period of time; and storing the copy object and the one ormore changes in the isolated environment according to the particularisolated storage scheme. The plurality of isolated storage schemes caninclude, at least, (i) a first isolated storage scheme in which the copyobject and the one or more changes are stored in an isolated space innon-volatile memory, and (ii) a second isolates storage scheme in whichthe copy object and the one or more changes are stored in an isolatedspace in volatile memory. The particular isolated storage scheme caninclude the first isolated storage scheme when the copy object isdetermined to have less than a threshold likelihood of requiringmultiple mappings within the threshold period of time. The copy objectand the one or more changes can be stored in the isolated space innon-volatile memory until being mapped to the actual object.

The particular isolated storage scheme can include the second isolatedstorage scheme when the copy object is determined to have at least athreshold likelihood of requiring multiple mappings within the thresholdperiod of time. The copy object and the one or more changes can bestored in the isolated space in volatile memory until being mapped tothe actual object. The computer-implemented method can includedetermining whether one or more limits on storage in the isolated spacein volatile memory has been reached. The copy object and the one or morechanges can be flushed from the isolated space in volatile memory andmapped to the actual object in response to determining that the one ormore limits have been reached. The one or more limits can include anupper limit on a number of objects stored in the isolated space involatile memory. The one or more limits can include an upper limit on anumber of isolated processes working on the copy object. The one or morelimits can include an upper limit on a number of changes applied to thecopy object while in the isolated space in volatile memory. The one ormore limits can include an upper limit on a length of time that the copyobject is permitted to be stored in the isolated space in volatilememory before being mapped to the actual object. The volatile memory canbe main memory for the computer system. The non-volatile memory can beone or more storage devices for the computer system.

Certain implementations may provide one or more advantages. For example,user convenience can be appropriately balanced against security risksthat may be posed from applying changes from processes running inisolation. A proactive permission scheme can provide greater usabilityby obtaining user permission in advance of any changes, which allows allchanges applied to the process to be mapped back to the actual processwithout subsequent user input. However, such a scheme may pose a greatersecurity risk on the computer system by not asking the user forpermission for each individual change that may take place, as done witha reactive permission scheme that is less convenient for a user (e.g.,prompting the user for permission for each change). By applyingdifferent permission schemes to different isolated processes based onthe security risk that they pose, a balance between user convenience andsecurity on the computer system can be maximized (e.g., allowing lessrisky processes to make changes under a proactive permission scheme andrestricting changes from more risky processes to a reactive permissionscheme).

In another example, grouping (batching) similar changes in a reactivescheme can reduce the number of times that user is asked to providepermission while still permitting the system to operate in a reactivemode of operation. For instance, if there is a write( ) command applyingmultiple changes to a file/memory, an isolation process can wait untilall of changes are performed and then ask for user permission to applyall of the changes together instead after asking the user for everysingle write. Such grouping mechanism can be applied in a variety ofdifferent contexts, such as with regard to security-sensitive tasks thataccess sensitive information (e.g., private user information, financialinformation). Batch reactive approaches can be more convenient than purereactive approach in that it can reduce the number of times a user isasked to provide permission. Batch reactive schemes may, however, stillpose risks since some changes in a batch may be different than others interms of security level. Such risks can be minimized by, for example, byensuring that changes are batched/grouped so that actions in abatch/group impose the same risk level to the system.

In a further example, grouping (batching) similar changes for userpermission can allow a user to have a more complete picture of thespectrum of changes that will be applied, and to make a more informeddecision regarding whether to approve the changes. For instance, sincemost processes create child processes that have the same access policy,required objects, and the same read/write sequences, sets of parent andchild processes in an execution state are likely to apply changes to theobjects at the same time (or very small delta time). By groupingtogether such changes, which are likely to impact the same objects, auser can make a more informed and efficient decision regarding whetherto apply changes as opposed to approving each change individually, whichmay not provide an overview of the collective changes that are beingapplied.

In another example, grouping (batching) similar changes for userpermission can also improve memory and CPU performance. For instance,minimizing the number of times that a CPU interacts with memory(non-volatile memory, volatile memory, main memory) can improve acomputing device's performance, particularly for machines with slow I/Odevices. If multiple processes are requesting that similar changes (orany other similarity in terms of type of change, children processes ofone parent process, similar objects, location of copy object, etc.) beapplied, it can be more efficient to group them together and save timeand resources for those actions.

In a further example, proactive mechanisms can be selected to providegreater resource efficiency (e.g., memory usage, CPU usage) thanreactive mechanisms based on proactive mechanisms being able to beimplemented without context switch overhead to stop a kernel level taskand calling user level tasks to prompt a user and to receive his/herpermission, as done with a reactive mechanism. For instance, whenever aprocessor suspends a task in order to apply changes, such as to receivereactive user input, there can be resource-demanding context switchprocedures in the system. Proactive mechanisms can provide greaterefficiency versus reactive mechanisms since there is no additional taskscheduling/context switch/etc. caused by proactive mechanisms, whereasreactive mechanisms can use such additional task scheduling/contextswitches/etc., which are inefficient operations during a monotonousprocess execution period. Such context-switching overhead can directlyaffect system performance and memory/CPU utilization. For instance, ifthe number of copy processes that are in an execution state increases,which can likely increase the amount of time that the system needs toswitch between them, then the system performance can degrade.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features and advantages willbe apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1A-B are a conceptual diagram of an example computer system forapplying and mapping process changes according to various permissionschemes.

FIG. 2 depicts an example computer system for mapping changes toprocesses.

FIGS. 3A-D are flowcharts of an example technique for assessing risksposed by computer processes.

FIG. 4 illustrates a schematic diagram of an exemplary generic computersystem.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This document generally describes techniques, systems, program products,and computing devices for applying and mapping changes from isolatedprocesses to actual system resources (e.g., files, network settings,registry entries, etc.) based on one or more selected permission schemesfor the isolated processes. For example, mapping procedures for copyversions of critical resources to the actual versions may be implementedin different ways. User confirmation/permission for mapping such changesmay be needed depending on, for example, the importance level of theobject (e.g., user or system files, etc.) and/or number of attempts tomake changes to the object. For instance, if the isolated process ischanging a system file in order to modify some I/O configurations (e.g.,turn BLUETOOTH or webcam ON/OFF), it may be necessary to ask for userpermission immediately to make such changes; however, making somechanges in user files (e.g., text documents) may not need userpermission until the changes are going to be mapped to the actual files.

There can be trade-offs between security (e.g., restricting/allowingchanges to be applied) and convenience (e.g., requesting user permissionfor changes). For example, if an isolated process is expected to makemultiple changes in several critical system files, it may not be userfriendly to ask for user permission for every single mapping that thesystem performs to the copy object. On the other hand, not asking forsuch permissions for mappings may pose a security risk and be hazardousto the system. In addition to the number of user permissions requiredfor mapping a copy object to the actual object in the system, which canbe a function of critical changes an isolated process may apply to thecopy object, the number of times that an isolated process is called (theprocess itself and/or its children) during system operation time candirectly affect the mapping complexity and overhead. In order tomaximize the trade-off between security and convenience of the system,different permission schemes can be selected for isolated processed.

For example, to better balance between the number of mappings needed forisolated objects/processes and the number of changes mapped to theactual objects, different permission schemes may be applied based on,for example, the characteristics of the objects (e.g., likelihood thatthe objects will change system files vs. user files, number of changesexpected). For instance, proactive permission schemes can be used thatforce users to provide permission whenever an isolated process needsaccess to an object and a copy of it is going to be provided (e.g.,fetch a copy of the actual object). In such a case, irrespective to theoperations on the object (e.g., read or write) that the isolated processwould perform, the permission for mapping is asked at the fetch timewhen the first copy of the object is created. This can allow theisolated process to apply any changes directly to the copy object andmap them to the actual object when the process is over (eitherimmediately after process termination or when scheduled by the system)and without subsequent user permission. This approach can obtain userpermission when an isolated process transition to the running state butmay not ask for any further permission after that. Such exampleproactive schemes can be a more user friendly approach that may causesome unwilling changes to the actual objects (less secure) since theuser will not be prompted by all details about the changes that isolatedprocesses may apply to different objects in the system.

In another example, reactive permission schemes can be used in whichsystems ask for user permission reactively based upon any changes (writeoperation) that are to be applied to the copy object (and/or when thechanges on the copy object are mapped to the actual object). Suchreactive permission schemes can be more secure than proactive approachessince the permissions are obtained per change (change to the copy objectand/or changes that are going to be mapped to the actual object). Thesereactive approaches, however, may be less user-friendly, especially forprocesses that make several changes to multiple objects when in therunning state, since each change can require additional user input,which can cause disturbances to the normal operation of the system.

Permission schemes, such as proactive and/or reactive permissionschemes, may additionally and/or alternatively shift obtaining userpermission to mapping time (e.g., once at the beginning of the mappingtime under proactive permission schemes, for each individual change tobe mapped with reactive permission schemes), which may be lessdisruptive to users. However, postponing such modifications untilmapping phase may not always be possible. For example, if two processes(one isolated and the other not) are in the running state at the sametime and need to make changes to the same object simultaneously (eventhough one of them is making changes to the copy version), it can begood practice to ensure consistency between the two processes and theobjects they are working with. For instance, if consistency is notmaintained for two different versions (actual and copy) as changes aremade across the two versions, it may be impossible to merge such changesat a later time (e.g., some changes may be incompatible across theobjects used by the isolated and not isolated processes). Consistencycan be maintained by mapping changes, for example, in manners similar tothose used by versioning systems, such as SubVersion systems. Forinstance, when two processes (isolated and not isolated) are working ontwo different versions of an object (copy and actual) and none of themis performing write operation on the object, there may be no need foruser permission and/or mapping during the running phase. However, it maybe necessary to map changes to both versions of the object when onechanges. Concurrent modification controls can be used to maintainconsistency across different processes using different versions of anobject.

In addition to using different permission schemes based on the type ofisolated process and/or object that is being used, different isolatedmemory spaces can be used to store copy versions (e.g., objects) and thechanges to be applied thereto. When in the running state, a process(control segment) and its corresponding object (actual or copy) aremoved from disk to the main memory (and some data blocks to the cache).Isolated memory space that is used for the process may be in any of avariety of locations, such as on the disk (example non-volatile memory),main memory (example volatile memory), and/or cache (example volatilememory). The isolated memory space that is used can be selected based ona variety of factors, such as the state of the process and/or mappingphases. For example, if no mapping is required (e.g., based on theproactive/reactive approaches and other settings discussed earlier)until the process is terminated or until a specific time (e.g., mappingis periodically performed every 24 hours or when system reboots), thecopy version and the changes can be stored on an isolated space on thedisk (similar to actual objects). In another example, for approachesthat use multiple mappings (e.g., process terminates and starts multipletimes a day or setting is reactive or the concurrent write operationoccurs), it may be inefficient to store the object on the disk and,instead, an isolated memory space may be created on the main memory.Such an example use of an isolated space in main memory can help reduce,for example, the mapping overhead especially if mapping happensfrequently. For instance, the actual and copy objects can both be in themain memory and isolated main memory, respectively, and immediatemappings (those necessary for version control and object consistency)can be performed accordingly and the final mapping on the object (afterprocess termination) is performed on the disk.

The use of an isolated space in main memory can be limited based on anyof a variety of factors. For instance, the isolated memory space cankeep track of all changes applied to copy objects and, therefore, mayincrease in size over time as the number of objects not mapped to theactual memory space increases. Moreover, if mapping is postponed to theprocess termination of multiple isolated processes (and/or children ofan isolated process and/or other isolated processes) the number ofchanges and their sequence may become complex and hard to managesimultaneously. Thus, the system may set limits on the use of theisolated space in main memory, which can force some changes to be mappedbefore, for example, process termination. Any of a variety of limits canbe used, such as upper limits on the number of objects being stored inthe isolated memory space, number of isolated processes working on thesame copy object, number of changes applied to an object while in theisolated memory space (before mapping), maximum times objects can beleft unmapped inside the isolated memory space, and/or any combinationthereof.

FIGS. 1A-B are a conceptual diagram of an example computer system 100for applying and mapping process changes according to various permissionschemes. The example computer system 100 can be any of a variety ofcomputing environments, including individual computing devices (e.g.,laptop computers, desktop computers, mobile computing devices, wearablecomputing device, computer server) and/or networked groups of computingdevices (e.g., server system, cloud computing system, client-serversystem). The computer system 100 includes an example file system 102that stores files for processes, such as actual objects, that are usedto execute the processes on the computer system 100, and an exampleisolated environment 104 that includes one or more isolated spaces involatile (e.g., RAM, cache) and/or non-volatile memory (e.g., storagedevice) that are used to execute copies of the processes in isolation onthe computer system 100.

FIGS. 1A-B depict an example actual object 106 for a process that, aspart of being run in isolation, is copied to create a correspondingexample copy object 108 in the isolated environment 104 to which one ormore changes 110 are applied and then mapped back to the actual object106. FIG. 1A depicts using an example proactive permission scheme toapply the changes 110 to the copy object and to map the changes 110 backto the actual object 106. FIG. 1B depicts using an example reactivepermission scheme to apply the changes 110 to the copy object and to mapthe changes 110 back to the actual object 106. The computer system 100can select between the example permission schemes (e.g., proactive,reactive, reactive batch, other permission schemes) based on any of afactors, such as characteristics of the actual object 106/copy object108/corresponding process (e.g., likelihood of making system changes,likelihood of making changes to user file, history of making systemchanges, history of making changes to user files) and/or risk assessmentfor the actual object 106/copy object 108/corresponding process. Forexample, the example proactive permission scheme (FIG. 1A) can beselected for a process that is to be run in isolation and has a historyof making no system changes and few user-space changes (e.g., changestored content files). In another example, the example reactivepermission scheme (FIG. 1B) can be selected for a process that is to berun in isolation and has a history of making several system changes(e.g., toggle wireless transmission settings, activate/deactivate webcamera).

A variety of other factors can additionally and/or alternatively be usedby the computer system 100 to select between the example permissionschemes. For example, system performance (e.g., memory utilization, CPUutilization) at the time that a process is being instantiated at run orexecution time can be another factor. For instance, if systemperformance is low—the memory and CPU are busy with multiple processes(high memory and CPU utilization) at a running state and multipleobjects stored in an isolated space are not mapped yet—a proactiveapproach can be selected based on proactive approaches using fewersystem resources for context switching and user permissions. On theother hand, when the memory utilization and CPU utilization is low(system performance is high) with only a few process are in a runningstate and few objects in an isolation space, a reactive approach can beselected to provide a greater level of security for the system withoutdrastically impacting the overall system performance.

In another example, a trust score can be assigned to processes and usedas a factor by the computer system 100 to select between permissionschemes. For instance, trust scores can be determined for processesbased on information regarding previous operation of the processes, suchas the previous running times of processes when operating under areactive approach and/or historical information for files associatedwith processes, such as how many times files required mappings and/or anumber/type of files/objects a process needed to change during previousoperation. A trust score for a process can initially be set to a lownumber that indicates a low level of trust for the process and each timethe process runs, for example, in a reactive mode and a user allows itto map its changes, the trust score can be increased. After multipletimes running in a reactive mode and obtaining user permission, whichcan cause the trust score to increase, the process can be permitted tobe included in grouping (batching) mechanism mode as discussed above.However, other events and/or actions may decrease a trust score for aprocess, such as a user declining permission requests for a process(e.g., declining at least a threshold number of permission requests,declining a specific number of iterations of permission requests),updates/upgrades/patches being applied to processes (e.g.,updates/upgrades/patches may introduce unknown bugs or vulnerabilitiesthat will cause a trust score to be lowered), and/orupdates/upgrades/patches being applied to the operating system (e.g.,operating system updates/upgrades/patches may lower all trust scoresbased on potential effects of new features/settings/procedures/etc.defined in the new operating system version on processes running on theoperating system).

Processes that have at least a first threshold trust score (indicating amoderate amount of trust) can be permitted to be included in grouping(batching) mechanisms (processes with less the first threshold trustscore—low level of trust—may not be permitted to operate in agroup/batching mechanism). Additionally, processes that have at least asecond threshold score (greater than the first threshold score) thatindicates a high level of trust can be permitted to operate under aproactive approach. For instance, after running multiple times in agrouping/batching approach and receiving user permission to applychanges, which can increase the trust score for a process, the processcan have a trust score that is greater than or equal to the secondthreshold trust score so as to permit it to operate in a proactive mode.Trust scores can be determined based on a variety of additional factors,such as the example characteristics and/or risk assessment for the ofthe actual object 106/copy object 108/corresponding process describedabove.

Referring to FIG. 1A, in response to determining that a proactivepermission scheme should be used for the copy object 108, the computersystem 100 can request user permission, as indicated by step A (112),before fetching a copy of the actual object 106 and running it in theisolated environment 104, as indicated by step B (114). For example, inresponse to a user selecting an application associated with the actualobject 106 and the computer system 100 determining that the processshould be run in isolation using a proactive permission scheme, thecomputer system 100 can output (e.g., display, audibly output, hapticprompt) a prompt for a user to provide permission for the application toapply and/or map any changes to the file system 102 that are made whilethe application is running. In response to the user providing permissionfor such changes (e.g., selecting a button, providing verbal permission,providing particular movement-based input), the computer system 100 canproceed to fetch a copy of the actual object 106 to instantiate the copyobject 108 in the isolated environment.

With the permission having been granted under the example proactivepermission scheme, the computer system 100 can proceed to apply thechanges 110 to the copy object 108 within the isolated environment 104,as indicated by step C (116), and to map those changes from the isolatedenvironment 104 to the actual object 106 in the (non-isolated) filesystem 102, as indicated by step D (118).

Referring to FIG. 1B, in response to determining that a reactivepermission scheme should be used for the copy object 108, the computersystem 100 can fetch a copy of the actual object 106 and running it inthe isolated environment 104 without first obtaining user permission forchanges to be applied/mapped to the copy object, as indicated by step B′(120). Step B′ can be similar to step B (114). For example, in responseto a user selecting an application associated with the actual object 106and the computer system 100 determining that the process should be runin isolation using a reactive permission scheme, the computer system 100can proceed to fetch a copy of the actual object 106 to instantiate thecopy object 108 in the isolated environment without first obtaining userpermission.

However, in response to a change being detected that is to be applied toand/or for the copy object 108, the computer system 100 can request userpermission to apply the change, as indicated by step A′ (122). Step A′can be similar to step A (112), but can be performed in response to eachchange that is detected for the copy object 108 while it is being run inthe isolated environment 104. For example, the computer system 100 canoutput (e.g., display, audibly output, haptic prompt) a prompt for auser to provide permission for the copy object 108 to make each change,such as turning the web camera on/off and/or communicating with a remoteserver system, that is requested by the copy object 108 while it isrunning in the isolated environment. In response to the user providingpermission for such changes (e.g., selecting a button, providing verbalpermission, providing particular movement-based input), the computersystem 100 can proceed to apply the changes 110 to the copy object 108(and/or to other objects/system resources on behalf of the copy object108), as indicated by step C′ (124). Step C′ can be similar to step C(116), but the performance of step C′ may be conditioned on the userpermission being received at step A′ (122). The permitted changes 110that are approved by the user and applied to the copy object 108, can bemapped to the actual object 106, as indicated by step D′ (126). Step D′can be similar to step D (118). In some implementations, a reactivepermission scheme may alternatively/additionally obtain user permissionsfor each change at the mapping phase (step D′).

FIG. 2 depicts an example computer system 200 for mapping changes toprocesses. The example system 200 can be similar to the system 100described above with regard to FIGS. 1A-B. For example, the computersystem 200 can perform steps A-D and/or A′-D′ based on, for example,characteristics of processes to be run in isolation. The computer system200 can be any of a variety of appropriate computer systems, such asindividual computing devices (e.g., laptops, desktop computers, mobilecomputing devices, computer server) and/or networked computing devices(e.g., server system, cloud-based computer system, client-serversystem).

The computer system 200 includes one or more processors 202 and anoperating system 204 for the computer system 200 that is run using theprocessors 202 to provide a computing environment on the computer system200. The computer system 200 can include an actual cache 208, memory210, and file system 212 that are in a native namespace and used by theprocessors 202 and the operating system 204 to execute processes thatare not in isolation. The computer system 200 also includes an isolatedenvironment 224 (similar to the isolated environment 104) that includesan isolated cache 214, isolated memory 216, and an isolated file system218 that can be restricted from the namespace (and other systemresources/settings) for the non-isolated space used by processors 202and/or operating system 204.

The example fetching steps described above with regard to steps B and B′can be performed by creating copies of actual objects, which may bestored across one or more of the cache 208, the memory 210, and the filesystem 212, and instantiating the copies in the isolated environment 224(e.g., across one or more of the isolated cache 214, the isolated memory216, and the isolated file system 218). Applying changes a controlobject, as described above with regard to steps C and C′, can beperformed within the isolated environment 224, for example, by applyingchanges from the isolated cache 214 to data/objects (e.g., the controlobject, other objects, isolated environment settings) in the isolatedmemory 216 and/or to files (e.g., the control object, other objects,isolated environment settings) stored in the isolated file system 218.

The computer system 200 includes a process manager 206 that isprogrammed to manage a variety of details regarding the execution ofisolated processes, such as whether or not processes are to be executedin the isolated environment 224, which of a plurality of permissionschemes (e.g., proactive permission scheme, reactive permission scheme,combination/hybrid of proactive and reactive permission schemes (e.g.,batching/grouping reactive permission scheme), other permission schemes)are to be used for processes executed in the isolation environment 224,enforcing the selected permission scheme (e.g., requesting userpermission, blocking various operations (fetching, applying changes,mapping) until appropriate user permissions are obtained), identifyingsituations when version control may be appropriate (e.g., actual andcopy objects being executed simultaneously for same process),implementing versioning controls when appropriate (e.g., mapping changesbetween actual and copy objects being executed concurrently), and/ormapping changes from the isolated environment 224 to the non-isolatedenvironment (cache 208, memory 210, file system 212). The processmanager 206 can be implemented in any of a variety of ways, such asthrough software (e.g., applications, operating system process),hardware (e.g., ASIC), firmware, or any combination thereof.

The process manager 206 can use an input subsystem 220 and outputsubsystem 222 that are part of the computer system 200 to obtain userpermissions for various actions (e.g., proactive permissions, reactivepermissions). The input subsystem 220 can include any of a variety ofcomponents through which a user can provide input, such as touchscreens,keyboards, physical buttons, cameras, microphones, accelerometers,gyroscopes, magnetometers, and/or other appropriate input devices. Theoutput subsystem 222 can include any of a variety of components throughwhich a user can provide output, such as displays, speakers, hapticfeedback devices, and/or other appropriate output devices.

FIGS. 3A-D are flowcharts of an example technique 300 for assessingrisks posed by computer processes. The example technique 300 can beperformed by any of a variety of appropriate computer systems and/orcomputing devices, such as the computer system 100 and/or the computersystem 200.

Referring to FIG. 3A, a request to run a particular process is received(302). For example, a user can select an application to run on thecomputer system 200 through the user subsystem 220. In response toreceiving the request, a determination can be made as to whether to runthe particular process in isolation (304). For example, the programmanager 206 can determine, based on any of a variety of factors (e.g.,previous behavior of process when executed on computer system 200,process having been flagged, certification/authentication of processbeing from trusted source), whether the selected process poses apotential risk to the computer system 200 and can determine whether theprocess should be run in isolation (e.g., in the isolation environment224). In response to determining that the particular process should runin isolation, a particular permission scheme can be selected from amonga plurality of permission schemes (306). For example, the processmanager 206 can determine whether a proactive, reactive, or otherpermission scheme should be used to apply and map changes from theisolated process back to the actual process. Such selection of apermission scheme can be based on a variety of factors, such ascharacteristics of the particular process and/or copy objects being runin the isolated environment 224.

A variety of other factors can additionally and/or alternatively be usedby the process manager 206 to select a permission scheme for a process.For example, the historical process management of a process can be usedas parameter factor in selecting a permission scheme. For instance,historical process management can include performance efficiency (e.g.,number of mappings, number of context switches, number of system filesand user files, its impact on the memory and CPU usage, etc.) of aprocess as described above. Trust scores, which may be based, at leastin part, on historical process management, can additionally be used asfactors for selecting permission schemes. The process manager 206 mayalso consider system factors at the moment the process is called to berun, such as the system performance (e.g., memory and/or CPU usage) atthat time, any security alert/log generated recently in the system (mayincrease the risk probability), and/or other appropriate systemperformance factors. For example, if an anti-virus process has recentlyprompted detection of some malicious files/processes, the systemsecurity level can increase to “very high” and, consequently, theisolation and mapping mechanisms can also be very restricted.

In implementations in which a proactive permission scheme is determinedto be appropriate, a user can be prompted to provide permission toapply/map changes in advance of the changes being made (307) and userinput providing the permission can be received (309). Such permissioncan be received before a copy object for the particular process isfetched (308). In implementations in which a proactive permission schemeis not used, the copy object can be fetched without first obtaining userpermission (308).

A mapping frequency for changes to the copy object can be estimated(310) and used to select an isolated storage scheme to use for the copyobject (312). For example, the process manager 206 can determine whethera copy object is likely to map changes more than a threshold number oftimes (e.g., more than 1, 2, 5, 10) within a threshold time period(e.g., 1 hour, 24 hours, 1 week), based on the estimate, can determinewhether to store the copy object and changes thereto, for example, innon-volatile memory (example storage scheme) or volatile memory (anotherexample storage scheme). The copy objects and changes thereto can bestored according to the selected storage scheme (314). For example, in astorage scheme that includes storing the copy object and changes theretoin volatile memory, the process manager 206 can store the copy objectand its changes in the isolated cache 214 and/or the isolate memory 216.

The particular process can be run in isolation with the copy object(316) and, when changes are generated, they can be applied to the copyobject (318). In implementations in which a reactive permission schemeis selected, the application of the changes can be contingent upon auser being prompted for permission to apply the changes (317) and theuser providing the requested permission (319). For example, the processmanager 206 can prompt the user for permission through the outputsubsystem 222 and receive user permission through the input subsystem220.

Changes can be mapped to the actual object (320). In someimplementations, changes may be mapped without further user input, suchas when a proactive permission scheme is being used. In someimplementations, the timing and/or permissions for mapping such changesto the actual object can be based on additional factors, such as thoseoutline for sub-techniques 330, 350, and 370 in FIGS. 3B-D, which can beperformed in combination with the technique 300.

Referring to FIG. 3B, a sub-technique 330 is depicted in which userpermission to map the changes is prompted (332) and received (334). Forexample, the sub-technique can be performed as part of a reactivepermission scheme.

Referring to FIG. 3C, sub-technique 350 is depicted in which anindication is obtained that there is another version of the copy object(e.g., concurrently running and corresponding actual object) that isrunning (352). In response to changes being detected in the copy object,those changes can be mapped to the other corresponding object so as toavoid irreconcilable inconsistencies between the two objects (354). Thesub-technique 350 can be performed in combination with the sub-technique330, when appropriate, before mapping the changes to the correspondingother object (320).

Referring to FIG. 3D, sub-technique 370 is depicted in which adetermination is made as to whether storage limits for storing the copyobject and changes thereto in an isolated space (e.g., volatile memoryin the isolated environment 224, non-volatile memory in the isolatedenvironment 224) has been reached (372). For example, a variety oflimits can be set, for example, on storage in an isolated portion ofvolatile memory, such as a limit on a number of object and/or changesthat can be stored, a limit on a number of isolated processes that canapply to a particular copy object, a limit on a number of changes thatcan be applied to the copy object while in the isolated space involatile memory, a limit on a length of time that the copy object ispermitted to be stored in the isolated space in volatile memory beforebeing mapped to the actual object, or any combination thereof. Inresponse to one or more of the storage limits being reached, the copyobject and/or changes thereto can be mapped (374). The examplesub-technique 370 can be performed in combination with thesub-techniques 330 and/or 350.

FIG. 4 illustrates a schematic diagram of an exemplary generic computersystem. The system 400 can be used for the operations described inassociation with the processes 300 according to some implementations.The system 400 may be included in the system 500.

The system 400 includes a processor 410, a memory 420, a storage device430, and an input/output device 440. Each of the components 410, 420,430, and 420 are interconnected using a system bus 450. The processor410 is capable of processing instructions for execution within thesystem 400. In one implementation, the processor 410 is asingle-threaded processor. In another implementation, the processor 410is a multi-threaded processor. The processor 410 is capable ofprocessing instructions stored in the memory 420 or on the storagedevice 430 to display graphical information for a user interface on theinput/output device 440.

The memory 420 stores information within the system 400. In oneimplementation, the memory 420 is a computer-readable medium. In oneimplementation, the memory 420 is a volatile memory unit. In anotherimplementation, the memory 420 is a non-volatile memory unit.

The storage device 430 is capable of providing mass storage for thesystem 400. In one implementation, the storage device 430 is acomputer-readable medium. In various different implementations, thestorage device 430 may be a floppy disk device, a hard disk device, anoptical disk device, or a tape device.

The input/output device 440 provides input/output operations for thesystem 400. In one implementation, the input/output device 440 includesa keyboard and/or pointing device. In another implementation, theinput/output device 440 includes a display unit for displaying graphicaluser interfaces.

Embodiments of the subject matter, the functional operations and theprocesses described in this specification can be implemented in digitalelectronic circuitry, in tangibly-embodied computer software orfirmware, in computer hardware, including the structures disclosed inthis specification and their structural equivalents, or in combinationsof one or more of them. Embodiments of the subject matter described inthis specification can be implemented as one or more computer programs,i.e., one or more modules of computer program instructions encoded on atangible nonvolatile program carrier for execution by, or to control theoperation of, data processing apparatus. Alternatively or in addition,the program instructions can be encoded on an artificially generatedpropagated signal, e.g., a machine-generated electrical, optical, orelectromagnetic signal that is generated to encode information fortransmission to suitable receiver apparatus for execution by a dataprocessing apparatus. The computer storage medium can be amachine-readable storage device, a machine-readable storage substrate, arandom or serial access memory device, or a combination of one or moreof them.

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus can include special purpose logic circuitry, e.g., an FPGA(field programmable gate array) or an ASIC (application specificintegrated circuit). The apparatus can also include, in addition tohardware, code that creates an execution environment for the computerprogram in question, e.g., code that constitutes processor firmware, aprotocol stack, a database management system, an operating system, or acombination of one or more of them.

A computer program (which may also be referred to or described as aprogram, software, a software application, a module, a software module,a script, or code) can be written in any form of programming language,including compiled or interpreted languages, or declarative orprocedural languages, and it can be deployed in any form, including as astandalone program or as a module, component, subroutine, or other unitsuitable for use in a computing environment. A computer program may, butneed not, correspond to a file in a file system. A program can be storedin a portion of a file that holds other programs or data (e.g., one ormore scripts stored in a markup language document), in a single filededicated to the program in question, or in multiple coordinated files(e.g., files that store one or more modules, sub programs, or portionsof code). A computer program can be deployed to be executed on onecomputer or on multiple computers that are located at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

The processes and logic flows described in this specification can beperformed by one or more programmable computers executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Computers suitable for the execution of a computer program include, byway of example, can be based on general or special purposemicroprocessors or both, or any other kind of central processing unit.Generally, a central processing unit will receive instructions and datafrom a read-only memory or a random access memory or both. The essentialelements of a computer are a central processing unit for performing orexecuting instructions and one or more memory devices for storinginstructions and data. Generally, a computer will also include, or beoperatively coupled to receive data from or transfer data to, or both,one or more mass storage devices for storing data, e.g., magnetic,magneto optical disks, or optical disks. However, a computer need nothave such devices. Moreover, a computer can be embedded in anotherdevice, e.g., a mobile telephone, a personal digital assistant (PDA), amobile audio or video player, a game console, a Global PositioningSystem (GPS) receiver, or a portable storage device (e.g., a universalserial bus (USB) flash drive), to name just a few.

Computer readable media suitable for storing computer programinstructions and data include all forms of nonvolatile memory, media andmemory devices, including by way of example semiconductor memorydevices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks,e.g., internal hard disks or removable disks; magneto optical disks; andCD-ROM and DVD-ROM disks. The processor and the memory can besupplemented by, or incorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subjectmatter described in this specification can be implemented on a computerhaving a display device, e.g., a CRT (cathode ray tube) or LCD (liquidcrystal display) monitor, for displaying information to the user and akeyboard and a pointing device, e.g., a mouse or a trackball, by whichthe user can provide input to the computer. Other kinds of devices canbe used to provide for interaction with a user as well; for example,feedback provided to the user can be any form of sensory feedback, e.g.,visual feedback, auditory feedback, or tactile feedback; and input fromthe user can be received in any form, including acoustic, speech, ortactile input. In addition, a computer can interact with a user bysending documents to and receiving documents from a device that is usedby the user; for example, by sending web pages to a web browser on auser's client device in response to requests received from the webbrowser.

Embodiments of the subject matter described in this specification can beimplemented in a computing system that includes a back end component,e.g., as a data server, or that includes a middleware component, e.g.,an application server, or that includes a front end component, e.g., aclient computer having a graphical user interface or a Web browserthrough which a user can interact with an implementation of the subjectmatter described in this specification, or any combination of one ormore such back end, middleware, or front end components. The componentsof the system can be interconnected by any form or medium of digitaldata communication, e.g., a communication network. Examples ofcommunication networks include a local area network (“LAN”) and a widearea network (“WAN”), e.g., the Internet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of what may beclaimed, but rather as descriptions of features that may be specific toparticular embodiments. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

What is claimed is:
 1. A computer-implemented method comprising:receiving, at a process manager running on a computer system, a requestto run a particular process on the computer system; determining, by theprocess manager, whether the particular process is to be run inisolation on the computer system; selecting, by the process manager andin response to determining that the particular process is to be run inisolation, a particular permission scheme from among a plurality ofpermission schemes based, at least in part, on one or morecharacteristics of the particular process, wherein each of the pluralityof permission schemes defines a different set of permission requirementsfor applying changes to a process being run in isolation; fetching, bythe process manager and according to the particular permission scheme, acopy object that corresponds to an actual object for the particularprocess, wherein the copy object is instantiated in an isolatedenvironment on the computer system; running the particular process inisolation on the computer system by executing the copy object in theisolated environment; applying, by the process manager and according tothe particular permission scheme, one or more changes to the copyobject; obtaining, by the process manager, an indication that anotherversion of the actual object is running as part of another process onthe computer system; and in response to obtaining the indication thatanother version of the actual object is running as part of anotherprocess on the computer system, mapping, by the process manager andaccording to the particular permission scheme, the one or more changesin the copy object to the actual object.
 2. The computer-implementedmethod of claim 1, wherein the plurality of permission schemes include,at least, (i) a proactive permission scheme in which user permission isobtained in advance of all changes being received for the copy object,and (ii) a reactive permission scheme in which user permission isobtained in response to each change that is received for the copyobject, and (iii) a reactive batching permission scheme in which userpermission is obtained in response to a batched group of changes thatare received for the copy object.
 3. The computer-implemented method ofclaim 2, wherein the particular permission scheme comprises theproactive permission scheme.
 4. The computer-implemented method of claim3, further comprising: outputting, by the computer system and beforefetching the copy object, information to prompt a user to providepermission for changes to the copy object in advance of any changesbeing made; and receiving, at the computer system and before fetchingthe copy object, user input comprising permission for changes to thecopy object, wherein the copy object is fetched in response to the userinput being received.
 5. The computer-implemented method of claim 2,wherein the particular permission scheme comprises the reactivepermission scheme.
 6. The computer-implemented method of claim 5,further comprising: outputting, by the computer system after fetchingthe copy object and before applying the one or more changes to the copyobject, information to prompt a user to provide permission for each ofthe one or more changes to the copy object; and receiving, at thecomputer system and before applying the one or more changes to the copyobject, user input comprising permission for each of the one or morechanges to the copy object, wherein the one or more changes are appliedto the copy object in response to the user input being received.
 7. Thecomputer-implemented method of claim 5, further comprising: outputting,by the computer system after applying the one or more changes to thecopy object and before mapping the one or more changes to the actualobject, information to prompt a user to provide permission for each ofthe one or more changes to the copy object; and receiving, at thecomputer system and before mapping the one or more changes to the actualobject, user input comprising permission for each of the one or morechanges to the copy object, wherein the one or more changes are mappedto the copy object in response to the user input being received.
 8. Acomputer-implemented method comprising: receiving, at a process managerrunning on a computer system, a request to run a particular process onthe computer system: determining, by the process manager, whether theparticular process is to be run in isolation on the computer system:selecting, by the process manager and in response to determining thatthe particular process is to be run in isolation, a particularpermission scheme from among a plurality of permission schemes based, atleast in part, on one or more characteristics of the particular process,wherein each of the plurality of permission schemes defines a differentset of permission requirements for applying changes to a process beingrun in isolation: fetching, by the process manager and according to theparticular permission scheme, a copy object that corresponds to anactual object for the particular process, wherein the copy object isinstantiated in an isolated environment on the computer system: runningthe particular process in isolation on the computer system by executingthe copy object in the isolated environment: applying, by the processmanager and according to the particular permission scheme, one or morechanges to the copy object; mapping, by the process manager andaccording to the particular permission scheme, the one or more changesin the copy object to the actual object; determining a likelihood thatthe copy object will require multiple mappings to the actual objectwithin a threshold period of time; selecting a particular isolatedstorage scheme from among a plurality of isolated storage schemes based,at least in part, on the likelihood that the copy object will requiredmultiple mappings within the threshold period of time; and storing thecopy object and the one or more changes in the isolated environmentaccording to the particular isolated storage scheme.
 9. Thecomputer-implemented method of claim 8, wherein the plurality ofisolated storage schemes include, at least, (i) a first isolated storagescheme in which the copy object and the one or more changes are storedin an isolated space in non-volatile memory, and (ii) a second isolatesstorage scheme in which the copy object and the one or more changes arestored in an isolated space in volatile memory.
 10. Thecomputer-implemented method of claim 9, wherein: the particular isolatedstorage scheme comprises the first isolated storage scheme when the copyobject is determined to have less than a threshold likelihood ofrequiring multiple mappings within the threshold period of time, thecopy object and the one or more changes are stored in the isolated spacein non-volatile memory until being mapped to the actual object.
 11. Thecomputer-implemented method of claim 9, wherein: the particular isolatedstorage scheme comprises the second isolated storage scheme when thecopy object is determined to have at least a threshold likelihood ofrequiring multiple mappings within the threshold period of time, thecopy object and the one or more changes are stored in the isolated spacein volatile memory until being mapped to the actual object.
 12. Thecomputer-implemented method of claim 11, further comprising: determiningwhether one or more limits on storage in the isolated space in volatilememory has been reached, wherein the copy object and the one or morechanges are flushed from the isolated space in volatile memory andmapped to the actual object in response to determining that the one ormore limits have been reached.
 13. The computer-implemented method ofclaim 12, wherein the one or more limits include an upper limit on anumber of objects stored in the isolated space in volatile memory. 14.The computer-implemented method of claim 12, wherein the one or morelimits include an upper limit on a number of isolated processes workingon the copy object.
 15. The computer-implemented method of claim 12,wherein the one or more limits include an upper limit on a number ofchanges applied to the copy object while in the isolated space involatile memory.
 16. The computer-implemented method of claim 12,wherein the one or more limits include an upper limit on a length oftime that the copy object is permitted to be stored in the isolatedspace in volatile memory before being mapped to the actual object. 17.The computer-implemented method of claim 9, wherein the volatile memorycomprises main memory for the computer system.
 18. Thecomputer-implemented method of claim 9, wherein the non-volatile memorycomprises one or more storage devices for the computer system.
 19. Asystem comprising: one or more processors and one or more computerstorage media storing instructions that are operable, when executed bythe one or more processors, to cause the one or more processors toperform operations comprising: receiving, at a process manager runningon a computer system, a request to run a particular process on thecomputer system; determining, by the process manager, whether theparticular process is to be run in isolation on the computer system;selecting, by the process manager and in response to determining thatthe particular process is to be run in isolation, a particularpermission scheme from among a plurality of permission schemes based, atleast in part, on one or more characteristics of the particular process,wherein each of the plurality of permission schemes defines a differentset of permission requirements for applying changes to a process beingrun in isolation; fetching, by the process manager and according to theparticular permission scheme, a copy object that corresponds to anactual object for the particular process, wherein the copy object isinstantiated in an isolated environment on the computer system; runningthe particular process in isolation on the computer system by executingthe copy object in the isolated environment; applying, by the processmanager and according to the particular permission scheme, one or morechanges to the copy object; mapping, by the process manager andaccording to the particular permission scheme, the one or more changesin the copy object to the actual object; determining a likelihood thatthe copy object will require multiple mappings to the actual objectwithin a threshold period of time; selecting a particular isolatedstorage scheme from among a plurality of isolated storage schemes based,at least in part, on the likelihood that the copy object will requiredmultiple mappings within the threshold period of time; and storing thecopy object and the one or more changes in the isolated environmentaccording to the particular isolated storage scheme.
 20. A systemcomprising: one or more processors and one or more computer storagemedia storing instructions that are operable, when executed by the oneor more processors, to cause the one or more processors to performoperations comprising: receiving, at a process manager running on acomputer system, a request to run a particular process on the computersystem; determining, by the process manager, whether the particularprocess is to be run in isolation on the computer system; selecting, bythe process manager and in response to determining that the particularprocess is to be run in isolation, a particular permission scheme fromamong a plurality of permission schemes based, at least in part, on oneor more characteristics of the particular process, wherein each of theplurality of permission schemes defines a different set of permissionrequirements for applying changes to a process being run in isolation;fetching, by the process manager and according to the particularpermission scheme, a copy object that corresponds to an actual objectfor the particular process, wherein the copy object is instantiated inan isolated environment on the computer system; running the particularprocess in isolation on the computer system by executing the copy objectin the isolated environment; applying, by the process manager andaccording to the particular permission scheme, one or more changes tothe copy object; obtaining, by the process manager, an indication thatanother version of the actual object is running as part of anotherprocess on the computer system; and in response to obtaining theindication that another version of the actual object is running as partof another process on the computer system, mapping, by the processmanager and according to the particular permission scheme, the one ormore changes in the copy object to the actual object.
 21. Anon-transitory computer-readable medium having stored thereoninstructions, which, when executed by one or more computers, cause theone or more computers to perform operations comprising: receiving, at aprocess manager running on a computer system, a request to run aparticular process on the computer system; determining, by the processmanager, whether the particular process is to be run in isolation on thecomputer system; selecting, by the process manager and in response todetermining that the particular process is to be run in isolation, aparticular permission scheme from among a plurality of permissionschemes based, at least in part, on one or more characteristics of theparticular process, wherein each of the plurality of permission schemesdefines a different set of permission requirements for applying changesto a process being run in isolation; fetching, by the process managerand according to the particular permission scheme, a copy object thatcorresponds to an actual object for the particular process, wherein thecopy object is instantiated in an isolated environment on the computersystem; running the particular process in isolation on the computersystem by executing the copy object in the isolated environment;applying, by the process manager and according to the particularpermission scheme, one or more changes to the copy object; mapping, bythe process manager and according to the particular permission scheme,the one or more changes in the copy object to the actual object;determining a likelihood that the copy object will require multiplemappings to the actual object within a threshold period of time;selecting a particular isolated storage scheme from among a plurality ofisolated storage schemes based, at least in part, on the likelihood thatthe copy object will required multiple mappings within the thresholdperiod of time; and storing the copy object and the one or more changesin the isolated environment according to the particular isolated storagescheme.
 22. A non-transitory computer-readable medium having storedthereon instructions, which, when executed by one or more computers,cause the one or more computers to perform operations comprising:receiving, at a process manager running on a computer system, a requestto run a particular process on the computer system; determining, by theprocess manager, whether the particular process is to be run inisolation on the computer system: selecting, by the process manager andin response to determining that the particular process is to be run inisolation, a particular permission scheme from among a plurality ofpermission schemes based, at least in part, on one or morecharacteristics of the particular process, wherein each of the pluralityof permission schemes defines a different set of permission requirementsfor applying changes to a process being run in isolation; fetching, bythe process manager and according to the particular permission scheme, acopy object that corresponds to an actual object for the particularprocess, wherein the copy object is instantiated in an isolatedenvironment on the computer system; running the particular process inisolation on the computer system by executing the copy object in theisolated environment; applying, by the process manager and according tothe particular permission scheme, one or more changes to the copyobject; obtaining, by the process manager, an indication that anotherversion of the actual object is running as part of another process onthe computer system; and in response to obtaining the indication thatanother version of the actual object is running as part of anotherprocess on the computer system, mapping, by the process manager andaccording to the particular permission scheme, the one or more changesin the copy object to the actual object.